m and m 13 - Anticholinergic Drugs

Question 1

What cholinergic receptor subtype to atropine, scopolamine and glycopyrrolate target?

Answer 1

Antimuscarinic receptors

Question 2

What are the two functional groups present on anticholinergics? What is the bond type linking these 2 functional groups?

Answer 2

Aromatic acid and organic base linked with ester bond

Question 3

What are he 3 muscarinic receptor subtypes and their locations?

Answer 3

M1 - Neuronal
M2 - Cardiac
M3 - Glandular

Question 4

What happens as you go higher than the normal clinical doses for the antimuscarinic agents?

Answer 4

Start to lose specificity

Question 5

What is the effects of antimuscarinics on CV function (re: AV node and PR interval)? What happens with low doses of atropine?

Answer 5

Increases conduction through AV node and shortens the PR interval
Low dose atropine causes paradoxical bradycardia

Question 6

What is the effect of antimuscarinics on ventricular function?

Answer 6

Usually no effect

Question 7

What is the possible CV side effect of antimuscarinics?

Answer 7

Can cause atrial arrythmias and nodal (junctional rhythms

Question 8

Whats is the significance of antimuscarinics and presynaptic muscarinic receptors?

Answer 8

Presynaptic muscarinic receptors inhibit Norepi release, therefore antimuscarinics will increase NE release

Question 9

Usually, antimuscarinics don’f affect the peripheral vasculature. What is the exception?

Answer 9

Atropine in large doses can cause dilation of cutaneous blood vessels, causing atropine flush

Question 10

What is the effect of antimuscarinics on respiratory secretions and dead space (mechanism of latter)?

Answer 10

WIll decrease secretions and increase dead space (secondary to relaxation of the bronchial smooth muscle relaxation)

Question 11

Signs of antimuscarinics cerebral excitation include? (3)

Answer 11

Excitation, restlessness and hallucinations

Question 12

Signs of antimuscarinics cerebral depression include? (2)

Answer 12

Sedation and amnesia

Question 13

What is the medication that is particularly good at reversing cerebral effects of antimuscarinics?

Answer 13

Physostigmine - can cross BBB

Question 14

WHat is the effects of antimuscarinics on gastric secretions, motility and the LES?

Answer 14

Decreased secretions
Decreased motility
Decreased pressure in the LES

Question 15

What are the two effects of antimuscarinics on the eye?

Answer 15

Mydriasis (pupilary dilation)

Cycloplegia (inability to accomodate to near vision)

Question 16

True or false, acute angle glaucoma is common side effect of systemic antimuscarinics

Answer 16

False - not after systemic administration *** check this

Question 17

What is the effect of antimuscarinics on the GU system? Mechanism?

Answer 17

Will cause relaxation of bladder smooth muscle and cause urinary retention

Question 18

What is the effect of antimuscarinics on sweat glands? What is the “syndrome”?

Answer 18

Can inhibit sweat glands, block thermoregulation leading to “atropine fever”

Question 19

True or false, atropine is a quaternary amine?

Answer 19

False, tertiary amine

Question 20

What is the most efficacious anticholinergic for treating bradyarrythmias? What group of patients should not get atropine?

Answer 20

Atropine

Avoid in patients with CAD - might not tolerate the tachycardia and increase O2 demand

Question 21

How is atropine related to ipratropium? What property of ipratropium makes it good for treating lung pathology?

Answer 21

Ipratropium is a derivative of atropine, a a quaternary ammonium structure. This prevents systemic absorption when used in lungs

Question 22

How is scopolamine structurally different from atropine?

Answer 22

Has an epoxide on the heterocyclic ring

Question 23

Which is a more potent antisialagogue, atropine or scopolamine? Which is more likely to cause CNS effects?

Answer 23

Scopolamine for both

Question 24

Why is scopolamine useful as a transdermal agent? What are 2 possible uses?

Answer 24

It is lipid soluble

Used for PONV and motion sickness

Question 25

What types of patients is scopolamine contraindicated in, i,e. what pathology?

Answer 25

Closed angle glaucoma

Question 26

How is glycopyrolate different from atropine?

Answer 26

It has a quatenary amine, has both a cyclopentane and pyridine moiety

Question 27

What are the 2 major uses of glycopyrolate?

Answer 27

Decreased salivary and respiratory gland secretions

Question 28

What route of administration is associated with increased HR after glycopyrrolate admin?

Answer 28

IV but not IM.

Question 29

What other drug classes will predispose patients to anticholinergic syndrome?

Answer 29

TCAs
Antihistamines
Antipsychotics
(All have anticholinergic effects)

Question 30

Neostigmine, pyridostigmine, physostigmine and edrophonium are all cholinesterase blockers. Which is best for reversing anticholinergic toxicity and why?

Answer 30

Physostigmine - only one that isnt quaternary amine and can cross the BBB